u/Easy-World189

I need some advice. My cats are 1.5 years old, both sisters and not separated since birth, at first they were besties always cuddling and everything. Now they’re no more baby’s but teenies and they no longer touch or groom each other I’ve noticed they don’t spend any time together and already thought it was weird but now they started hissing and growling at each other. At this point I don’t think it’s just weird I think they really have a problem. I already noticed the tension and tried some feliway optimum. But the hissing is new which means the feliway didn’t work. What should I do? They sometime hiss when they only looking at each other.